The grain boundary character distribution effect on the flow stress of polycrystals: The influence of crystal lattice texture

Abstract

The grain size of a polycrystalline aggregate has an important effect on its properties. Several properties of materials, such as the yield and flow stresses, ductility and hardness have been suggested to show a linear dependence on (average size of grains) −1 2 . A number of models which justify the grain size effect are based on the assumption that the grains in a polycrystal have the same size and the grain boundaries the same properties. Grain boundaries are characterized by differences in their structure and, as a result, in their properties. An experimental study of the grain boundary strengthening effect in a 316L austenitic stainless steel has been carried out on a series of specimens obtained employing a powder-forming process and produced by conventional thermo-mechanical processing. The Brinell hardness was measured and analysed as a function of (grain size) −1 2 . The experimental data, in general, confirm the Hall—Petch relationship. A significant difference is observed in the values of the K H constants. This difference is discussed in terms of the influence of crystal texture on the strengthening effect of the grain boundaries.